Flexible flat cables (FFC) have been much used in computers, liquid crystal display devices, mobile phones, printers, automobiles, home appliances, copy machines and other various electronic, electric and mechanical products for electrical connections requiring flexibility or mobility, or various forms of wiring. Such flexible flat cables (FFC) generally have a structure in which an adhesive-applied substrate film and the like are attached to a single surface or both surfaces of a single conductor or a plurality of conductors to cover the conductors.
Flexible flat cable (FFC) are used in electronic devices or machines having motions such as rotation or sliding movements, and used for smoothly transferring electric signals even in exothermic environments by the operation of the electronic devices and the motion of the machines while flexibly transforming with structural changes caused by the motion of the electronic devices or the machines. As a result, an insulation film for a flexible flat cable (FFC) covering the flexible flat cable (FFC) requires tensile strength and flexibility for motions such as rotation or sliding movements, and requires high stability at high temperatures and flame retardancy.
As such an insulation film for a flexible flat cable (FFC), Japanese Patent Application Laid-Open Publication No. H08-60108 discloses a non-halogen flame retarding flat cable using an adhesive layer formed with a polyimide film and a phosphorous-modified saturated polyester copolymer.
However, there is a problem in that such an insulation film does not have sufficient tensile strength and flexibility properties.